Hello Codeforces,

I am glad to invite you all to participate in Codeforces Round 1101 (Div. 2), which will be held on May/30/2026 17:35 (Moscow time). You will be given 6 problems to solve in 2 hours, one of which to be split into two subtasks.

All problems are authored by me. :) I also would like to thank the following people:

• Um_nik for pre-reviewing the round
• Proof_by_QED for the excellent coordination and guidance.
• __baozii__, _istil, Dragos, nifeshe, sammyuri, CatalanConvolution, cry, omsincoconut, SpyrosAliv, wakanda-forever, chromate00, mannyw, nik_exists, simplelife, and ianding for testing and providing a wonderful feedback for the round.
• Alexdat2000 for Russian translations.
• MikeMirzayanov for Polygon and Codeforces.

The scoring distribution is as follows: 500 — 1000 — (750 + 1000) — 2000 — 2750 — 3250

EDIT: Change the scoring of C from (1000 + 750) to (750 + 1000)

sammyuri, myst-6 and I are absolutely chuffed to bits to invite you all to have a go at Codeforces Round $$${12}_{10}$$$ (Spectral::Cup 2026 Round 2 (Codeforces Round 1100, Div. 1 + Div. 2)), kicking off at May/23/2026 17:35 (Moscow time).

There will be 9 absolute cinema problems for you to solve over the course of 3 hours, some problems will have multiple parts. This round will be combined for Division 1 and Division 2 and will be rated for everyone.

I’d like to raise a glass to the following brilliant minds for making this whole thing possible:

• Dominater069 for splendid coordination.
• Um_nik for preliminary review.
• The fine assembly of testers: arvindf232, EvenImage, Geothermal, Sana, Wansur, p0tato, __baozii__, Aotsuki, Dragos, catgirl, Monogon, nifeshe, Proof_by_QED, lucaski2, efishel, is_i, Argentum47, reirugan, naneosmic, chromate00, Nyemot, simplelife, eric899.
• moonpole for remembering to test.
• Alexdat2000 for Russian translation.
• MikeMirzayanov and KAN for Codeforces and Polygon.
• You for participating.

Score distribution: $$$500 - 750 - (750 + 1250) - 2000 - 2500 - 2500 - 3250 - 4000 - 5000$$$

UPD: editorial

UPD2: Congratulations to the winners!

1. maroonrk

2. jiangly

3. ksun48

4. Radewoosh

5. maspy

6. turmax

7. ecnerwala

8. StarSilk

9. NanYan

10. SleeplessSouris

Now a few words from our sponsor.

Spectral::Technologies is an HFT fund – we build trading strategies and low-latency infrastructure for global markets. The people doing this: IMO, IOI, IPhO and All-Russian Olympiad medalists and top engineers – people who love the challenge and always want a bigger one. That's who Spectral was built for.

We are actively hiring! Check out our Quant roles:

• Junior Quant – 150–180k USD + profit sharing
• Middle Quant – 240–320k USD + profit sharing
• Senior Quant – 360–500k USD + profit sharing

We’re also hiring for C++, ML, and DevOps roles. Complete the application form to explore career opportunities with us.

We are excited to sponsor our second Round as part of Spectral::Cup 2026 — a three-round tournament where prizes get more valuable with every round.

Prizes for Round 2:

Top 30 will get laptop cases (390x290mm) + Codeforces-inspired anti-stress toys.

Make sure that you take part in at least two rounds to improve your chances to win the main prizes. We prepared bigger prizes for top performers by their final score in Spectral::Cup 2026. The final score is the sum of your best 2 results according to the GP500.

• Top-3 by final score will get (1st) MacBook Pro, (2nd) iPad Pro, (3rd) Whoop — or USDT equivalent to the prize value
• Top-15 by final score will get Claude subscription
• 30 random participants among top 500 based on the final score will get additional prizes

Code fast, think faster – see you in the next round of Spectral::Cup 2026!

Hello, Codeforces!

We are glad to invite you to participate in Codeforces Round 1099 (Div. 2), which will be help on May/21/2026 17:35 (Moscow time). You will be given of 6 problems and 2 hours to solve them. This round will be rated for the participants with a rating lower than 2100.

The problems are authored and prepared by xoxo, Kuyan, FairyWinx, sunkuangzheng, TheScrasse and Vladithur. Also, we want to express our sincere thank to people without whom this round would be impossible:

• FairyWinx, for the great round coordination

• Our testers: Wansur, FelixArg, Fakewave, yanb0, Dinmiax, Vitaly239239, 300iq, Iura_Shch, fishy15, KiruxaLight, sadovan, larush, SomethingNew, __baozii__, _istil, madlogic, -firefly- and ABalobanov.

• MikeMirzayanov and KAN for the great platforms Codeforces and Polygon.

The scoring distribution will be published later.

We hope you enjoy the round. Good Luck and Have Fun!

UPD. The scoring distribution will be as follows: $$$500 – 1000 – 1250 – 2000 – 2500 – 2750$$$

UPD: Editorial

Hello Codeforces!

The series of Educational Rounds continues thanks to the support of the Computer Science and Artificial Intelligence (CSAI) program at Neapolis University Pafos, with scholarships provided by JetBrains.

Educational Codeforces Round 190 (Rated for Div. 2) will start on May/18/2026 17:35 (Moscow time).

This round will be rated for the participants with rating lower than 2100. It will be held on extended ICPC rules. The penalty for each incorrect submission until the submission with a full solution is 10 minutes. After the end of the contest, you will have 12 hours to hack any solution you want. You will have access to copy any solution and test it locally.

The problems in this round will partially intersect with Saratov SU internal contest (scheduled for 17th of May), so if you are a student of Saratov SU who participates in it, you have to skip this round.

You will be given 6-7 problems and 2 hours to solve them.

The problems were invented and prepared by Adilbek adedalic Dalabaev, Maksim Neon Mescheryakov, Alex fcspartakm Frolov and me. Also, huge thanks to Mike MikeMirzayanov Mirzayanov for great systems Polygon and Codeforces.

Big shoutout to testers of the round: shnirelman, awoo and FelixArg! Thank you for testing the problems.

Last but not least our friends at Neapolis University Pafos also have a message for you:

The final admission round for the BSc in Computer Science and Artificial Intelligence at Neapolis University Pafos is now open.

Key Dates:

• Application deadline: June 9, 2026

• Mandatory Entrance Test: June 14, 2026

Apply for a chance to receive one of up to 40 JetBrains Foundation Scholarships covering:

• full tuition

• accommodation

• monthly stipend

• visa support

Start your application and prepare before the final deadline!

Good luck to all the participants! I hope you will find our problems both interesting and educational.

UPD: The editorial can be found here.

你好，Codeforces!

We (WDOI team) are delighted to invite you to participate in Codeforces Round 1098 (Div. 2), which will be held on May/16/2026 17:35 (Moscow time). You will be given $$$6$$$ problems, including two problems each having easy and hard versions, and $$$2$$$ hours and $$$15$$$ minutes to solve them. This round will be rated for the participants with rating lower than 2100.

The problems are authored and prepared by Sugar_fan and me.

The score distribution:

We would like to express our sincere thanks to the following individuals for their contributions and for making this round possible:

• Sugar_fan for his incredibly dedicated coordination and support,and he has also deleted some problems and modified some to make the round better.

• Um_nik for preliminary review of the round and giving me courage.

• Alexdat2000 for Russian translations.

• Otomachi_Una, juan_123, CirnoNine, fanhuaxingyu for their valuable contribution to the problems.

• EnofTaiPeople, _istil, Welcome24ever, Mitsukasa_Ayase, SATSKY_2025target_LGM, Serval, __baozii__, juan_123, Zheng_iii, Arpa, CirnoNine, Anoth3r, hushuqi_qwq, fanhuaxingyu, SunJude, ddndd, RioBlus, bluket, bzy, CSP_Sept, YoungLau, ihy, 2021cjx, alij_8, gouhhmumu for testing the round.

• MikeMirzayanov and KAN for the amazing platforms.

• And finally, You for participating.

We are a team made up of fans of both competitive programming and the Touhou Project. Although this isn’t our first time hosting contests on Codeforces — we previously organized Codeforces Round 796 (Div. 1) and Codeforces Round 796 (Div. 2) — I authored most of the problems in this round with little assistance. In 2022, most of our members were Olympiad in Informatics (OI) participants, but over the four years since then, many have stepped away from OI and competitive programming. While the older generation may eventually fade away, newcomers like me aim to keep our community alive by injecting fresh energy and passion into what we love. I hope this kind of pure love persists and carries on.

Across these six problems, you will meet characters with their own distinct personalities and beliefs.

Marisa stole Reimu’s takeout and vanished before the shrine maiden could react. Hungry and sharp-eyed, Reimu marched to the Scarlet Devil Mansion, challenged Remilia to a fierce game of Hisoutensoku, and claimed victory—along with her lunch. Near the Misty Lake, Cirno found a cold number frozen in the ice. With a child’s certainty, she reshaped it into a beautiful ice crystal, perfect and gleaming. Atop the Youkai Mountain, Sanae watched the stars and prayed for fortune, her quiet hopes rising with each passing light. Elsewhere, an Amanojaku teetered on the edge of ruin. In Yukari’s contest, it solved a problem others deemed impossible, reversing its fate and reclaiming its place.

Hearing of these scattered lives, Momoyo built a grand network across Gensokyo — linking shrines, mansions, and factions. Conflict gave way to conversation, and peace settled softly over the land. Harmony replaced trouble, and laughter returned to the air.

Help them overcome these trials through your logic, and find satisfaction in lending a hand. We hope you enjoy the round. Good Luck and Have Fun!

May Gensokyo’s peace endure — and may the real world, too, know such days.

UPD1: Tutorial

UPD2:

The top five (official):

1. the_chill
2. nguyenphong233
3. oleinikowc
4. edmondium23
5. mo_mo_yu

The top five (unofficial):

1. the_chill
2. nguyenphong233
3. oleinikowc
4. maspy
5. edmondium23

The first solvers :

• A. KALDESH

• B. maspy

• C1. shravani20

• C2. the_chill

• D. AntaresI

• E1. 2240711

• E2. A10ne

• F. A10ne

UPD3: Apology

The best and brightest programmers from around the world have gathered this week in Shanghai, China, for the highly anticipated 2026 Universal Cup Finals!

Event Details

• Date: Sunday, May 10th
• Start time: 11:00 AM CST (3:00 AM UTC)
• See participating teams
• Full schedule can be found here

Streaming

Witness the best contestants in the world as they push the boundaries of skill and strategy. You can be part of this event by following us online either on the English livestream or the Chinese livestream.

Prediction Game

Cheer for your favorite teams and predict the winners in our prediction game!

Mirror Contest

Join the mirror contest and compete in real-time with the finalists from anywhere in the world. Any Universal Cup registered team can participate. The mirror contest is available here, you may use your Universal Cup team account or register a new account to participate in the mirror contest.

Stay Tuned for the Conference

This isn't just a competition – it's a global celebration of competitive programming. Join us for The 2026 Universal Cup Conference for Competitive Programming on Monday, May 11th. Listen to insightful discussions with the brightest minds in the field.

The Conference will be streamed on the Universal Cup channel.

Nihao! Hello to all fans of competitive programming and Codeforces enjoyers!

On behalf of Tsinghua University’s Zhili College, we — your proud and slightly sleep-deprived Class of 2029 Information and Computational Science students — are happy to invite you to participate in Codeforces Round 1097 (Div. 1, Based on Zhili Cup 2026) and Codeforces Round 1097 (Div. 2, Based on Zhili Cup 2026), which will take place on May/06/2026 09:05 (Moscow time). Note the unusual start time of the round. You’ll have 2.5 hours to tackle 6 problems for both division 1 and division 2, the round will be rated for all participants.

The score distribution will be announced later.

This round’s problems are brought to you by the incredible AC-Automation, graphcity, erduolong, Ge_QingHui, rsrsr, yangyuxi, schrodingerstom, unputdownable, lyreqwq, wangzhifang, aleph1022 and LinRui. Special thank you to thebighead and CharlieV who also prepared problems that were ultimately not used in this round.

A massive THANK YOU to the following legends who made this event possible:

• The one and only KAN for his invaluable support in hosting the round.

• Our chad coordinator, SSerxhs for coordinating this round, finding testers, and providing moral and technical support.

• Our brilliant testers: XiaoXia, Liang_SYEA, fr200110217102, Nanani, Boboge, CReatiQ, triple__a, tarjen, permutation, SATSKY_2025target_LGM, fallleaves01, tiger2005 and turmax for testing and providing invaluable feedback.

• Our fantastic organisers: schrodingerstom, lyreqwq, LitDarkness and kevinliu251831 for the smooth operation of the contest.

• Our advisors Ruidong Wan, Yaqi Zhou, Yike Cao and Xi Wang from Zhili College for supporting our efforts and ensuring school approval.

• Special thanks to Tsinghua University’s Association of Algorithmic Competitions for their support and help.

• MikeMirzayanov and geranazavr555 for enabling this event through the amazing Codeforces platform.

Zhili Cup itself is an annual event hosted by Tsinghua University’s Zhili College along with its freshmen of ICS. We are delighted to meet you on Codeforces this year.

Good luck, and may your code be bug-free and your coffee cup never empty.

See you at the round!

UPD1: Score distribution

• Div. 1: 500−750−1500−2500−3500−4500
• Div. 2: 500−750−1000−1250−2250−3500

UPD2: The editorial has been published.

• https://codeforces.com/blog/entry/153567

Hello, Codeforces!

I am super excited to invite you to participate in Codeforces Round 1096 (Div. 3), which will take place on Apr/30/2026 17:35 (Moscow time). You will be given $$$2$$$ hours and $$$30$$$ minutes to solve $$$8$$$ problems. All problems were authored and prepared by me.

The round will be hosted by rules of educational rounds (extended ICPC). Thus, all solutions will be judged on preliminary tests during the round, and after the round, there will be a 12-hour phase of open hacks. After the open hack phase, all accepted solutions will be rejudged on successful hacks. Also, note that there is no score distribution but the usual penalty of 10 minutes for each wrong submission, following the rules of educational rounds.

Remember that only the trusted participants of the third division will be included in the official standings table. As it is written by link, this is a compulsory measure for combating unsporting behavior. To qualify as a trusted participant of the third division, you must:

• take part in at least five rated rounds (and solve at least one problem in each of them)
• do not have a rating of 1900 or higher at any moment in time.

Regardless of whether you are a trusted participant of the third division or not, if your rating is less than 1600, then the round will be rated for you (unless you register unrated).

I would like to thank the following people for making this round possible:

• cry for coordinating the round;
• __baozii__ for red testing;
• -firefly-, omsincoconut for orange testing;
• cgmoreda, SpyrosAliv, wuhudsm, Argentum47 for purple testing;
• mathtsai, chromate00 (VIP), Mousa for blue testing;
• simplelife for cyan testing;
• lina_os, Syrianooo for green testing;
• Vladosiya for statement translation and testing;
• MikeMirzayanov for developing Codeforces and Polygon.

Good luck, and most importantly, have fun!

UPD: Tutorial

Hello Codeforces!!!

We are delighted to invite you to participate in Codeforces Round 1095 (Div. 2), which will be held on [contest_time:2226]. You will be given $$$7$$$ problems, including one split into two subtasks (not necessarily placed adjacently), and $$$2$$$ hours $$$15$$$ minutes to solve them. This round will be rated for the participants with a rating lower than 2100.

The problems are authored and prepared by [user:wakanda-forever,2026-04-26] and [user:wuhudsm,2026-04-26].

The scoring distribution is as follows:

We would like to express our sincere thanks to the following individuals for their contributions and for making this round possible:

• [user:Proof_by_QED,2026-04-21] for his incredibly indelible coordination.
• [user:Um_nik,2026-04-21] for preliminary review of the round.
• [user:Alexdat2000,2026-04-21] for Russian translations.
• Our testers: [user:A_G,2026-04-21], [user:awesomeguy856,2026-04-21], [user:-firefly-,2026-04-21], [user:Dominater069,2026-04-21], [user:sammyuri,2026-04-21], [user:liympanda,2026-04-21], [user:IceKnight1093,2026-04-21], [user:physics0523,2026-04-21], [user:nik_exists,2026-04-21], [user:SpyrosAliv,2026-04-21], [user:Argentum47,2026-04-21], [user:DivinePunishment,2026-04-21], [user:omsincoconut,2026-04-21], [user:__baozii__,2026-04-21], [user:Edeeva,2026-04-21], [user:chromate00,2026-04-21], [user:shorya1835,2026-04-21], [user:AksLolCoding,2026-04-21], [user:Friedrich,2026-04-21], [user:simplelife,2026-04-21], [user:tridipta2806,2026-04-21], [user:_istil,2026-04-21], [user:expertaq,2026-04-22]
• [user:MikeMirzayanov,2026-04-21] and [user:KAN,2026-04-21] for the epic platforms.
• And finally, you for participating.

We hope you take part in the round and enjoy solving the problems. Good Luck and Have Fun!

UPD: Hacks will be disabled for the problems A to E.

UPD: Editorial

UPD: Congratulations to the winners!!!

Top 5 overall:

• [user:Nachia,2026-04-29]
• [user:Rubikun,2026-04-29]
• [user:hitonanode,2026-04-29]
• [user:StarSilk,2026-04-29]
• [user:BurnedChicken,2026-04-29]

Top 5 rated participants:

• [user:lunatide.tech,2026-04-29]
• [user:R_eeee,2026-04-29]
• [user:rns_jhm,2026-04-29]
• [user:hakuuuuya,2026-04-29]
• [user:Ke_Jie_Go,2026-04-29]

First solves:

• A: [user:Od_Ali,2026-04-29]
• B: [user:longago_06,2026-04-29]
• C: [user:2002chenhan,2026-04-29]
• D: [user:SATSKY_2025target_LGM,2026-04-29]
• E: [user:Nachia,2026-04-29]
• F: [user:Golovanov399,2026-04-29]
• G: [user:A10ne,2026-04-29]